JP7589332B2 - Terminal, wireless communication method, base station and system - Google Patents

Description

The present disclosure relates to a terminal, a wireless communication method , a base station , and a system in a next-generation mobile communication system.

Long Term Evolution (LTE) has been specified for the Universal Mobile Telecommunications System (UMTS) network with the aim of achieving higher data rates and lower latency (Non-Patent Document 1). In addition, LTE-Advanced (3GPP Rel. 10-14) has been specified with the aim of achieving higher capacity and greater sophistication over LTE (Third Generation Partnership Project (3GPP) Release (Rel.) 8, 9).

Successor systems to LTE (also known as, for example, 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 or later) are also being considered.

In the existing LTE system (LTE Rel. 8-15), radio link quality is monitored (Radio Link Monitoring (RLM)). When a Radio Link Failure (RLF) is detected by RLM, a request is made to the user equipment (User Equipment (UE)) to re-establish a Radio Resource Control (RRC) connection.

3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)”, April 2010

In NR (e.g., Rel. 15/16), it is being considered to implement a procedure for detecting beam failures and switching to another beam (which may also be called a Beam Failure Recovery (BFR) procedure, BFR, Link recovery procedures, etc.).

In future wireless communication systems (e.g., Rel. 17 and later, or 5G and later), it is expected that a terminal (UE) will communicate using multiple transmission/reception points (TRPs)/UE panels. In this case, it is conceivable that beam management (e.g., beam obstruction detection) will be performed in multiple TRPs/multiple UE panels.

However, how to control beam failure detection (BFD) or beam failure recovery (BFR) in each TRP/UE panel is an issue. If beam failure detection or beam failure recovery in each TRP/UE panel cannot be appropriately controlled, there is a risk of a decrease in communication throughput or a deterioration in communication quality.

The present disclosure has been made in consideration of these points, and one of its objectives is to provide a terminal, a wireless communication method , a base station , and a system that are capable of appropriately detecting beam faults or recovering from beam faults even when multiple transmission and reception points are used.

A terminal according to one aspect of the present disclosure includes a receiving unit that receives beam failure recovery (BFR) configuration information for a special cell (SpCell) and a secondary cell (SCell ) included in a cell group, and a control unit that controls the BFR to be performed using resources other than a physical uplink control channel (PUCCH) resource corresponding to the first TRP when a scheduling request (SR) for BFR for a first transmission/reception point (TRP) of the SpCell is triggered and a BFR for a second TRP of the SpCell is triggered before a medium access control control element (MAC CE) corresponding to the SR is transmitted .

According to one aspect of the present disclosure, beam fault detection or beam fault recovery can be performed appropriately even when multiple transmission and reception points are used.

1 is a diagram showing an example of a beam recovery procedure in Rel. 15 NR. 2 is a diagram showing an example of a beam recovery procedure in Rel. 16 NR. 3A to 3C are diagrams illustrating an example of setting PUCCH resources and spatial relationships for a scheduling request. 4A-4C are diagrams showing an example of a problem with the BFR procedure when beam interference is detected on different TRPs between cells and when different TRPs are set between cells. 5A and 5B are diagrams illustrating an example of a method for configuring a PUCCH resource for SR according to the first aspect. FIG. 6 is a diagram showing another example of the method of configuring the PUCCH resource for SR according to the first aspect. FIG. 7 is a diagram for explaining an example of a BFR procedure according to the second aspect. 8A to 8C are diagrams for explaining another example of the BFR procedure according to the second aspect. FIG. 9 is a diagram for explaining another example of the BFR procedure according to the second aspect. 10A to 10C are diagrams for explaining another example of the BFR procedure according to the second aspect. 11A to 11C are diagrams for explaining an example of a BFR procedure according to the fifth aspect. FIG. 12 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 13 is a diagram illustrating an example of the configuration of a base station according to an embodiment. FIG. 14 is a diagram illustrating an example of the configuration of a user terminal according to an embodiment. FIG. 15 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment.

(Beam obstruction detection)
In NR, communication is performed using beamforming. For example, a UE and a base station (e.g., a gNB (gNodeB)) may use a beam used to transmit a signal (also called a transmission beam, Tx beam, etc.) and a beam used to receive a signal (also called a reception beam, Rx beam, etc.).

When beamforming is used, it is expected that radio link quality will deteriorate because it becomes more susceptible to interference from obstacles. This deterioration in radio link quality may lead to frequent radio link failures (RLFs). Since RLFs require cell reconnection, frequent RLFs lead to degradation of system throughput.

In NR, in order to suppress the occurrence of RLF, when the quality of a particular beam deteriorates, a procedure is performed to switch to another beam (which may be called Beam Recovery (BR), Beam Failure Recovery (BFR), L1/L2 (Layer 1/Layer 2) beam recovery, etc.). The BFR procedure may simply be called BFR.

In addition, beam failure (BF) in this disclosure may also be referred to as link failure.

Figure 1 is a diagram showing an example of a beam recovery procedure in Rel. 15 NR. The number of beams is an example and is not limited to this. In the initial state (step S101) of Figure 1, the UE performs measurements based on reference signal (RS) resources transmitted using two beams.

The RS may be at least one of a Synchronization Signal Block (SSB) and a Channel State Information RS (CSI-RS) for measuring channel states. The SSB may also be referred to as an SS/PBCH (Physical Broadcast Channel) block, etc.

The RS may be at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), a Mobility Reference Signal (MRS), a signal included in an SSB, an SSB, a CSI-RS, a DeModulation Reference Signal (DMRS), a beam-specific signal, etc., or a signal constructed by extending or modifying these. The RS measured in step S101 may be called an RS for beam failure detection (Beam Failure Detection RS (BFD-RS), RS for beam failure detection), or an RS for use in a beam recovery procedure (BFR-RS), etc.

In step S102, the UE cannot detect the BFD-RS (or the reception quality of the RS deteriorates) due to interference with radio waves from the base station. Such interference may occur, for example, due to obstacles, fading, interference, etc. between the UE and the base station.

The UE detects beam failure when a certain condition is met. The UE may detect the occurrence of beam failure, for example, when the Block Error Rate (BLER) is less than a threshold for all configured BFD-RS (BFD-RS resource configuration). When the occurrence of beam failure is detected, the lower layer (physical (PHY) layer) of the UE may notify (indicate) a beam failure instance to the upper layer (MAC layer).

The criteria for judgment are not limited to BLER, but may be Layer 1 Reference Signal Received Power (L1-RSRP) in the physical layer. Also, instead of or in addition to RS measurement, beam failure detection may be performed based on a downlink control channel (Physical Downlink Control Channel (PDCCH)). The BFD-RS may be expected to be quasi-co-located (QCL) with the DMRS of the PDCCH monitored by the UE.

Here, QCL is an index that indicates the statistical properties of a channel. For example, when a signal/channel and another signal/channel are in a QCL relationship, it may mean that it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameters (e.g., spatial Rx parameters) is the same between these different signals/channels (QCL with respect to at least one of these).

In addition, the spatial reception parameters may correspond to a reception beam (e.g., a reception analog beam) of the UE, and the beam may be identified based on a spatial QCL. The QCL (or at least one element of the QCL) in this disclosure may be read as sQCL (spatial QCL).

Information about BFD-RS (e.g., RS index, resource, number, number of ports, precoding, etc.), information about beam failure detection (BFD) (e.g., the above-mentioned threshold), etc. may be configured (notified) to the UE using higher layer signaling, etc. Information about BFD-RS may be referred to as information about BFR resources, etc.

In the present disclosure, higher layer signaling may be, for example, any one of RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information, etc., or a combination thereof.

The MAC signaling may be, for example, a Media Access Control Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. The broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

When a higher layer (e.g., a MAC layer) of the UE receives a beam failure instance notification from the PHY layer of the UE, the UE may start a predetermined timer (which may be called a beam failure detection timer). If the UE's MAC layer receives a certain number of beam failure instance notifications (e.g., beamFailureInstanceMaxCount set by RRC) before the timer expires, the UE's MAC layer may trigger a BFR (e.g., start one of the random access procedures described below).

The base station may determine that the UE has detected a beam failure if there is no notification from the UE or if it receives a predetermined signal (beam recovery request in step S104) from the UE.

In step S103, the UE starts searching for a new candidate beam to be used for new communication in order to recover the beam. The UE may select a new candidate beam corresponding to a specific RS by measuring the RS. The RS measured in step S103 may be called a new candidate RS, an RS for identifying a new candidate beam (New Candidate Beam Identification RS (NCBI-RS)), a CBI-RS, a CB-RS (Candidate Beam RS), or the like. The NCBI-RS may be the same as or different from the BFD-RS. The new candidate beam may simply be called a candidate beam or a candidate RS.

The UE may determine a beam corresponding to an RS that satisfies a specified condition as a new candidate beam. The UE may determine a new candidate beam, for example, based on an RS among the configured NCBI-RS whose L1-RSRP exceeds a threshold. Note that the criteria for determination are not limited to L1-RSRP. L1-RSRP for SSB may be referred to as SS-RSRP. L1-RSRP for CSI-RS may be referred to as CSI-RSRP.

Information regarding the NCBI-RS (e.g., RS resources, number, number of ports, precoding, etc.), information regarding the new candidate beam identification (NCBI) (e.g., the above-mentioned threshold), etc. may be configured (notified) to the UE using higher layer signaling, etc. Information regarding the new candidate RS (or NCBI-RS) may be obtained based on information regarding the BFD-RS. Information regarding the NCBI-RS may be referred to as information regarding NBCI resources, etc.

Note that BFD-RS, NCBI-RS, etc. may also be interpreted as radio link monitoring reference signal (Radio Link Monitoring RS (RLM-RS)).

In step S104, the UE that has identified the new candidate beam transmits a beam recovery request (Beam Failure Recovery reQuest (BFRQ)). The beam recovery request may be referred to as a beam recovery request signal, a beam failure recovery request signal, etc.

The BFRQ may be transmitted, for example, using at least one of an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), and a configured grant (configured grant (CG)) PUSCH.

The BFRQ may include information of the new candidate beam/new candidate RS identified in step S103. Resources for the BFRQ may be associated with the new candidate beam. The beam information may be notified using a beam index (Beam Index (BI)), a port index of a specific reference signal, an RS index, a resource index (e.g., a CSI-RS Resource Indicator (CRI), an SSB Resource Indicator (SSBRI)), etc.

In Rel. 15 NR, CB-BFR (Contention-Based BFR), which is a BFR based on a contention-based random access (RA) procedure, and CF-BFR (Contention-Free BFR), which is a BFR based on a non-contention-based random access procedure, are under consideration. In CB-BFR and CF-BFR, the UE may transmit a preamble (also called a RA preamble, random access channel (Physical Random Access Channel (PRACH)), RACH preamble, etc.) as a BFRQ using PRACH resources.

In CB-BFR, a UE may transmit a preamble randomly selected from one or more preambles. On the other hand, in CF-BFR, a UE may transmit a preamble that is assigned specifically to the UE by the base station. In CB-BFR, a base station may assign the same preamble to multiple UEs. In CF-BFR, a base station may assign a preamble individually to each UE.

Note that CB-BFR and CF-BFR may be referred to as CB PRACH-based BFR (contention-based PRACH-based BFR (CBRA-BFR)) and CF PRACH-based BFR (contention-free PRACH-based BFR (CFRA-BFR)), respectively. CBRA-BFR may be referred to as CBRA for BFR. CFRA-BFR may be referred to as CFRA for BFR.

Regardless of whether CB-BFR or CF-BFR is used, information regarding the PRACH resource (RA preamble) may be notified, for example, by higher layer signaling (such as RRC signaling). For example, the information may include information indicating the correspondence between the detected DL-RS (beam) and the PRACH resource, and a different PRACH resource may be associated with each DL-RS.

In step S105, the base station that detected the BFRQ transmits a response signal (which may be called a gNB response, etc.) to the BFRQ from the UE. The response signal may include reconfiguration information (e.g., configuration information of DL-RS resources) for one or more beams.

The response signal may be transmitted, for example, in a UE common search space of the PDCCH. The response signal may be notified using a PDCCH (DCI) scrambled with a Cyclic Redundancy Check (CRC) by a UE identifier (for example, a Cell-Radio RNTI (C-RNTI)). The UE may determine at least one of the transmit beam and the receive beam to be used based on the beam reconfiguration information.

The UE may monitor the response signal based on at least one of a control resource set for BFR (COntrol REsource SET (CORESET)) and a search space set for BFR.

For CB-BFR, contention resolution may be determined to be successful if the UE receives a PDCCH corresponding to its own C-RNTI.

Regarding the processing of step S105, a period may be set for the UE to monitor a response from a base station (e.g., a gNB) to the BFRQ. The period may be called, for example, a gNB response window, a gNB window, a beam recovery request response window, etc. The UE may retransmit the BFRQ if no gNB response is detected within the window period.

In step S106, the UE may transmit a message to the base station indicating that the beam reconfiguration is complete. The message may be transmitted, for example, via the PUCCH or the PUSCH.

BR success may represent, for example, reaching step S106. On the other hand, BR failure may represent, for example, a predetermined number of BFRQ transmissions or expiration of a beam-failure-recovery-timer.

Rel. 15 supports the use of a random access procedure to perform beam recovery procedures (e.g., BFRQ notification) in response to a beam failure detected in an SpCell (PCell/PSCell).

On the other hand, Rel. 16 supports performing a beam recovery procedure (e.g., BFRQ notification (step S104 in FIG. 1)) for a beam failure detected in an SCell by using at least one of a PUCCH (e.g., a scheduling request (SR)) transmission for BFR and a MAC CE (e.g., an UL-SCH) transmission for BFR (see FIG. 2).

For example, the UE may transmit information about beam failure using MAC CE-based two-step (SR transmission/MAC CE transmission). The information about beam failure may include information about the cell that detected the beam failure and information about a new candidate beam (or a new candidate RS index).

[Step 1]
If BF is detected, a PUCCH-BFR (Scheduling Request (SR)) may be transmitted from the UE to the SpCell (e.g., PCell/PSCell). The PUCCH-BFR may also be referred to as PUCCH-SR, PUCCH-SR for BFR, PUCCH for SR, or SR for BFR.

Next, a UL grant (e.g., DCI) for step 2 below may be transmitted from the PCell/PSCell to the UE. If a beam failure is detected and there is a MAC CE (or UL-SCH/PUSCH) for transmitting information about a new candidate beam, step 1 (e.g., transmitting a PUCCH for SR) may be omitted and step 2 (e.g., transmitting a MAC CE) may be performed.

[Step 2]
The UE may transmit information about the cell where the beam failure was detected (failed) (e.g., cell index) and information about the new candidate beam to the base station (PCell/PSCell/SCell) via an uplink channel (e.g., PUSCH) using the MAC CE. After that, through the BFR procedure, the QCL of the PDCCH/PUCCH/PDSCH/PUSCH may be updated to the new beam after a predetermined period (e.g., 28 symbols) after receiving a response signal from the base station.

Note that the numbers of these steps are merely for explanatory purposes, and multiple steps may be combined or the order may be changed. In addition, whether or not to perform BFR may be configured in the UE using higher layer signaling.

Incidentally, in future wireless communication systems (e.g., Rel. 17 and later, or 5G and later), beam management for UEs having multiple panels (multi-panel), or the extension of beam management using multiple transmission/reception points (multi-Transmission/Reception Points (TRP)), are being considered.

In beam failure detection/beam failure recovery in Rel. 17 and later, it is assumed that a BFRQ framework based on the SCell BFR BFRQ of Rel. 16 (e.g., BFRQ using two steps) will be supported. In this case, up to X PUCCH-SR resources (e.g., dedicated PUCCH-SR resource) may be configured in a cell group. X may be 1, 2, or more than 2.

In the present disclosure, the cell group may be, for example, at least one of a master cell group (MCG), a secondary cell group (SCG), and a PUCCH cell group. The MCG and the SCG may be groups configured in dual connectivity (DC). The PUCCH cell group may be a group configured in PUCCH transmission.

In addition, in Rel. 17 and later, it is also assumed that in a certain cell, beam failure detection/beam failure recovery will be performed for each of multiple TRPs (e.g., per-TRP BFR). For example, it is also possible that transmission of a scheduling request (SR) for BFD/BFR per TRP/TRP unit will be supported.

(Example of SR resource/PUCCH-SR resource configuration)
The SR resource/PUCCH-SR resource (hereinafter, referred to as PUCCH-SR resource) may be set in a predetermined unit. The predetermined unit may be, for example, a cell group. The PUCCH-SR resource may be read as a dedicated PUCCH-SR resource, a PUCCH resource for SR, or an SR-PUCCH resource.

For example, in a cell group, up to X PUCCH-SR resources may be configured/supported. X may be a fixed value (e.g., X=2) or may correspond to the number of TRPs to be configured/applied. At least one of the following SR settings 0, 1, and 2 may be supported for the SR setting.

<SR setting 0>
_X0 PUCCH resources (or PUCCH for SR) may be configured for an SR (e.g., SR index/SchedulingRequestID) in a cell group, and _Y0 spatial relationships may be configured for the PUCCH resources. Here, _X0 =1 and _Y0 =1 are shown (see FIG. 3A), but this is not limiting.

3A shows a case where one PUCCH resource for SR (here, PUCCH resource for SR #1) is configured for an SR configured in a cell group (or SpCell), and one spatial relationship (here, spatial relationship #1) is configured for the PUCCH resource for SR. Note that the numbers of _X0 and _Y0 are not limited to this.

SR setting 0 may apply the SR setting method for SCell BFR in Rel. 16.

<SR setting 1>
A maximum of _X1 PUCCH resources (e.g., dedicated PUCCH-SR resources) may be configured in a cell group for each SR (e.g., SR index/SchedulingRequestID), and _Y1 spatial relationships may be configured for the PUCCH resources. Here, _X1 =1 and _Y1 =2 are shown (see FIG. 3B), but this is not limited thereto. The PUCCH resource corresponding to spatial relationship #1 and the PUCCH resource corresponding to spatial relationship #2 may be associated with different TRPs.

3B shows a case where one PUCCH resource for SR (here, PUCCH resource for SR #1) is configured for an SR configured in a cell group (or SpCell), and two spatial relationships (here, spatial relationships #1 and #2) are configured for the PUCCH resource for SR. Note that the numbers of _X1 and _Y1 are not limited to this.

<SR Setting 2>
In the SR (e.g., SR index/SchedulingRequestID) for each cell group, up to X ₂ PUCCH resources (e.g., dedicated PUCCH-SR resources) are configured in the cell group, and Y ₂ spatial relationships are configured for each PUCCH resource. Here, X ₂ =2 (or more than 2) and Y ₂ =1 are shown (see FIG. 3C), but are not limited thereto.

FIG. 3C shows a case where two PUCCH resources for SR (here, PUCCH resources for SR #1 and #2) are configured for an SR configured in a cell group (or SpCell), and one spatial relationship (here, spatial relationship #1 and #2) is configured for each PUCCH resource for SR. FIG. 3C shows a case where different spatial relationships are configured for PUCCH resource for SR #1 and PUCCH resource for SR #2, but the same spatial relationship may be configured. Note that the numbers of X ₂ and Y ₂ are not limited to this. Also, multiple spatial relationships may be configured for each PUCCH resource.

The UE may receive at least one of the following information from the network (e.g., base station) using higher layer signaling/DCI: information regarding SRs in a cell group (e.g., SR index/SchedulingRequestID), information regarding PUCCH resources in a cell group (e.g., PUCCH-SR resources), and information regarding spatial relations (e.g., spatial relations) set for PUCCH resources.

The information on SR may be at least one of information indicating the SR index (or SchedulingRequestID) to be set and information indicating the number of SRs to be set. The information on PUCCH resources in a cell group may be at least one of information indicating PUCCH resources and information indicating the number of PUCCH resources to be set. The information on spatial relations may be at least one of information indicating spatial relations and information indicating the number of spatial relations to be set. In the present disclosure, spatial relations (e.g., spatial relation), beam, spatial filter, spatial domain filter, TCI state, and QCL may be interchangeable.

The UE may also receive information regarding the setting of cell-based/TRP-based BFR for each cell (e.g., a cell included in a cell group) from the network (e.g., a base station) using higher layer signaling/DCI. The information regarding the setting of cell-based/TRP-based BFR may be information indicating whether or not cell-based/TRP-based BFR is set/applied. Alternatively, the information regarding the setting of cell-based/TRP-based BFR may be information indicating the BFR type (cell-based/TRP-based BFR, or cell-specific BFR).

The UE may control the transmission of SR or PUCCH-SR based on at least one of the number of SRs (or the number of SR indices) set for each cell group and the BFR type (e.g., BFR per TRP/BFR per cell) set/applied to a specific cell included in the cell group. In this case, the UE may control the transmission of SR or PUCCH-SR based on at least one of the number of PUCCH resources set and the number of spatial relations set (or corresponding) to the PUCCH resources.

Each PUCCH-SR resource may be applied/configured corresponding to a different TRP. When beam failure recovery is triggered by the detection of beam failure, the PUCCH-SR resource may be selected based on the cell in which the beam failure is detected. For example, when a UE detects a beam failure for a first TRP among a first TRP and a second TRP configured in a certain cell, the UE may transmit an SR (or PUCCH) using a PUCCH-SR resource corresponding to the second TRP.

On the other hand, when a cell group includes multiple cells, the SR (or PUCCH) is transmitted from a specific cell (e.g., SpCell/PUCCH SCell) among the multiple cells. In this case, how to control UE operation when beam failure of TRP differs between cells (e.g., when beam failure is detected at different TRPs between cells, or when different TRPs are set between cells) becomes an issue.

<Case 1>
In an SCell that supports beam failure detection per TRP (per-TRP BF), a BFR SR (also called SR for BFR) is triggered based on beam failure of one TRP (e.g., TRP #a) and a PUCCH resource for SR is transmitted (see FIG. 4A). Beam failure detection per TRP (per-TRP BF) may be read as BFR per TRP (per-TRP BFR).

Figure 4A shows a case where a cell group includes SpCell and SCell#1-SCell#3, TRP-based BFR is configured for SpCell and SCell#1-SCell#2, and cell-based BFR is configured for SCell#3. Here, a case is shown where, when a beam failure of TRP#a of SCell#1 is detected, the UE transmits an SR for BFR using TRP#b of SpCell (or the PUCCH resource for SR corresponding to TRP#b).

In this case, the PUSCH for the MAC CE for BFR is scheduled by the UL grant transmitted from the base station based on the transmission of the SR for BFR. However, there may be cases where a beam failure of another TRP (e.g., TRP #b, or both TRP #a and #b) is detected in another SCell before the transmission of the MAC CE for BFR/before the cancellation of the SR for BFR.

For example, in FIG. 4A, after transmitting the PUCCH resource for SR corresponding to TRP#b based on the beam failure of TRP#a of SCell#1, it is possible to detect the beam failure of TRP#b of SCell#2 before transmitting the MAC CE for BFR. In such a case, how to control the BFR procedure (e.g., UE operation) becomes an issue. For example, the issue is whether to transmit the SR for BFR using the TRP#a of the SpCell (or the PUCCH resource for SR corresponding to TRP#a).

<Case 2>
It is also possible that beam interference may be detected on a TRP-by-TRP basis for one TRP within a specified period (e.g., simultaneously) in multiple SCells, and the TRP in which beam interference is detected may differ between SCells (see Figure 4B).

Figure 4B shows a case where a cell group includes SpCell, SCell#1-SCell#2, and TRP-based BFR is configured for SpCell and SCell#1-SCell#2. Here, it shows a case where the UE detects beam failure of TRP#a of SCell#1 and TRP#b of SCell#2.

In such a case, how to control the BFR procedure (e.g., UE operation) becomes an issue. For example, when transmitting a BFR SR in an SpCell, the issue is whether to use the SR PUCCH resource corresponding to TRP #a or the SR PUCCH resource corresponding to TRP #b.

<Case 3>
It is also possible that the TRP of the SpCell (e.g., the TRP set in the SpCell) and the TRP of the SCell (e.g., the TRP set in the SCell) are different (see FIG. 4C).

Figure 4C shows a case where a cell group includes SpCell, SCell#1-SCell#2, and BFR is configured on a TRP basis for SpCell and SCell#1-SCell#2. It also shows a case where TRP#a and TRP#b are configured for SpCell, TRP#b and TRP#c are configured for SCell#1, and TRP#a and TRP#c are configured for SCell#2. It also shows a case where a beam failure is detected for TRP#c of SCell#2.

In such a case, the problem is how to control the BFR procedure (e.g., UE operation). For example, when transmitting a BFR SR in an SpCell, the problem is which TRP-corresponding PUCCH resource for SR should be used.

The inventors focused on each case in which beam failure recovery procedures (e.g., beam failure detection/beam failure recovery request/UE operation based on beam failure recovery) are applied on a TRP basis, and considered the method of setting SR/transmitting SR in such cases, and came up with the present embodiment.

Below, an embodiment of the present disclosure will be described in detail with reference to the drawings. Each aspect may be applied alone or in combination. Each aspect below may be applied to at least one of the above cases 1-3, or may be applied to other cases. In other words, the present embodiment may be applied in a variety of cases, not limited to the above cases 1-3.

In the present disclosure, the UE may be a UE that transmits and receives data to and from a TRP using multiple panels. Each panel may correspond to a different TRP, one panel may correspond to multiple TRPs, or multiple panels may correspond to one TRP.

In this disclosure, a panel (or panel index) of a UE may correspond to a particular group. In this case, the UE may assume that the beams/RS of each group are measured on each panel of the UE. The UE may assume that it receives beams of multiple groups simultaneously (using different panels).

In the present disclosure, a TRP may be interchangeably read as a panel of TRPs (or base stations), an RS group, an antenna port group, a spatial relationship group, a QCL group, a TCI state, a TCI state group, a CORESET group, a CORESET pool, etc. Also, a TRP index may be interchangeably read as an RS group index, an antenna port group index, a QCL group index, a TCI state index, a TCI state group index, a CORESET group index, a CORESET pool index, etc.

In the present disclosure, a UE panel may be interchangeably referred to as an RS group, an antenna port group, a spatial relationship group, a QCL group, a TCI state group, a CORESET group, etc.

In the present disclosure, a panel may be associated with a group index of an SSB/CSI-RS group. Also, in the present disclosure, a panel may be associated with a TRP. Also, in the present disclosure, a plurality of panels may be associated with a group index for group beam-based reporting. Also, in the present disclosure, a panel may be associated with a group index of an SSB/CSI-RS group for group beam-based reporting.

In the present disclosure, the serving cell/cell may be replaced with PCell, PSCell, SpCell, or SCell. In the following description, an example is given in which two TRPs correspond to a serving cell, but three or more TRPs may correspond to a serving cell.

In the present disclosure, BFD RS in which beam failure has been detected, failed BFD RS, TRP in which beam failure has been detected, failed TRP, UE panel in which beam failure has been detected, and failed UE panel may be interpreted as interchangeable.

In this disclosure, A/B may be read as at least one of A and B, or A and B. In this disclosure, A/B/C may be read as at least one of A, B, and C.

(First aspect)
In the first aspect, a case will be described in which PUCCH resources for BFR SR are controlled based on the type of beam failure detection or beam failure recovery configured/applied to the SpCell/SCell.

In the present disclosure, the SpCell may be at least one of a primary cell (PCell) and a primary secondary cell (PSCell). Alternatively, the SpCell may be read as a cell that supports the transmission of the PUCCH.

The type of beam fault detection (BFD) or beam fault recovery (BFR) may indicate the unit at which beam fault detection or beam fault recovery is performed. For example, either a per-cell BFR or a per-TRP BFR may be set. A per-cell/per-TRP BFR may be read as a per-cell BFD/per-TRP BFR. A per-cell/per-TRP may be read as per cell/per TRP.

The PUCCH resource of the BFR SR set for a certain cell group/SpCell (or the PUCCH resource set for the BFR SR) may be controlled based on the BFR type set for the SpCell/the number of beam interference detection reference signal (BFD-RS) sets set for the SpCell (Option 1).

Alternatively, the PUCCH resources for BFR SR configured for a cell group/SpCell may be controlled based on the BFR type configured for the SCell/the number of beam interference detection reference signal (BFD-RS) sets configured for the SpCell (Option 2).

<Option 1>
The SR for BFR may support the configuration of multiple (e.g., two) PUCCH resources only when TRP-based BFR is configured in the SpCell (or when multiple (e.g., two) BFD-RS sets are configured) (see Figure 5A).

Figure 5A shows a case where a cell group includes SpCell, SCell#1-SCell#2, TRP-based BFR is configured for SpCell and SCell#1, and cell-based BFR is configured for SCell#2. In this case, the configuration of multiple SR PUCCH resources for the cell group (or SpCell) may be supported.

[Per-cell BFR/one PUCCH resource]
If cell-based BFR is configured in the SpCell (e.g., if one BFD-RS set is configured) or if BFR is not configured, the UE may assume that a maximum of one PUCCH resource is configured for the SR for BFR (see Figure 5B), regardless of whether cell-based/TRP-based BFR is configured in other cells (e.g., which SCells).

Figure 5B shows a case where a cell group includes SpCell, SCell#1 and SCell#2, a TRP-based BFR is configured for SCell#1, and a cell-based BFR is configured for SpCell and SCell#2. In this case, the cell group (or SpCell) may be configured such that the configuration of multiple SR PUCCH resources is not supported (one SR PUCCH resource is configured).

When cell-level BFR is configured for the SpCell, if the BFR is triggered by the BFR of the SCell (regardless of BFR type), the SR trigger procedure may be the same as in Rel. 16.

[TRP unit BFR/2 PUCCH resources]
When BFR is set for each TRP in the SpCell and the SR for BFR is configured with multiple (e.g., two) PUCCH resources, the PUCCH resources for SR may be associated with each TRP. In this case, the UE operation (e.g., the BFR procedure) may be the method shown in the second aspect.

When the TRP of the SpCell and the TRP of the SCell are the same (for example, when the same TRP is commonly configured), the association of the TRP of each cell with the PUCCH resource for SR is valid. For example, when a BFR of one TRP is triggered in a certain cell, the transmission of the SR for BFR may be controlled using a PUCH resource associated with a TRP in which no beam failure is detected (for example, a non-failed TRP).

In this case, higher layer parameters may be introduced to configure the TRP relationship (e.g., TRP and PUCCH resource association) between multiple cells (or CCs). The UE may control BFR operation based on the configuration configured in the higher layer. Also, a CC list may be created for serving cells that can assume the same TRP relationship (e.g., the same SR configuration for BFR as the SpCell).

For serving cells with the same TRP relationship across cells (or CCs), if a BFR of one TRP is triggered in a cell, the PUCCH resource associated with the TRP without beam failure may be transmitted. If a cell-based BFR or a TRP-based BFR with two TRP failures is triggered, at least one of Alt. 1-1 to Alt. 1-3 below may be applied.

If there is no same TRP relationship indication/setting between cells (or CCs), or if BFR is triggered in a serving cell where there is a different TRP relationship indication/setting between cells, at least one of Alt. 1-1 to Alt. 1-3 below may be applied.

When considering the case where the TRP of the SpCell and the TRP of the SCell are set differently, the PUCCH resource for SR and the TRP of the SCell may not be associated. Therefore, when a cell-based BFR/TRP-based BFR occurs in the SCell, the PUCCH resource for SR of either the PSCell may be used. Therefore, after the SR for BFR is triggered, the UE may apply at least one of the following Alt. 1-1 to Alt. 1-3.

[Alt. 1-1]
The UE transmits the SR for BFR using the default PUCCH resource for SR.

[Alt. 1-2]
The UE transmits the SR for BFR using two PUCCH resources for SR.

[Alt. 1-3]
The UE transmits the SR for BFR using a PUCCH resource for SR that is randomly selected.

<Option 2>
An SR for BFR having up to two PUCCH resources may be configured even when a cell-based BFR is configured in an SpCell (or when one BFD-RS set is configured), and when a TRP-based BFR is configured in one SCell (see Figure 6).

Figure 6 shows a case where a cell group includes SpCell, SCell#1 and SCell#2, a TRP-based BFR is configured for SCell#1, and a cell-based BFR is configured for SpCell and SCell#2. In this case, the configuration of multiple SR PUCCH resources for the cell group (or SpCell) may be supported.

In addition, when the SpCell is configured with BFR on a TRP basis (or when multiple BFD-RS sets (e.g., two) are configured), two PUCCH resources may be configured in the SR for BFR (see Figure 5A).

If cell-wide BFR is configured in the SpCel and one PUCCH resource for SR is configured, the operation of Rel. 16 may be used.

When cell-level BFR is configured in SpCel and two PUCCH resources for SR are configured, the third aspect may be applied.

When a TRP-unit BFR is configured in SpCel and two PUCCH resources for SR are configured, the second aspect may be applied.

(Second Aspect)
In the second aspect, an example of a BFR procedure in a case where a plurality of PUCCH resources for SR are configured in a cell group/SpCell is described. For example, an example of a UE operation in a case where another beam failure occurs before a MAC CE for BFR is transmitted after a BFR SR is triggered in a certain cell is described. The trigger of the BFR SR may be read as a BFR trigger.

Assume that a BFR is configured for each TRP in the SpCell, and an SR for BFR having multiple (e.g., two) PUCCH resources is configured. In this case, Case 2-1 and Case 2-2 are possible.

<Case 2-1>
When a beam failure is detected in a TRP in the SpCell and BFR/SR for BFR is triggered, only one PUCCH resource associated with another TRP (non-failed TRP) in the SpCell may be transmitted (see FIG. 7).

Figure 7 shows a case where a cell group includes SpCell, SCell#1 and SCell#2, TRP-based BFR is set for SpCell and SCell#1, and cell-based BFR is set for SCell#2. Here, it shows a case where, when a beam failure of TRP#a of SpCell is detected, the UE transmits an SR for BFR using TRP#b of SpCell (or the PUCCH resource for SR corresponding to TRP#b).

In this case, after SR is triggered (or PUCCH resources are transmitted), the following cases 2-1-1 to 2-1-3 are assumed before the MAC CE for BFR is transmitted.

<Case 2-1-1>
Assume that before the MAC CE for BFR is transmitted, a beam failure is also detected in another TRP (e.g., TRP #b) of the SpCell, and BFR (or SR for BFR) is triggered (see FIG. 8A). In this case, at least one of the following options 2-0 to 2-3 may be applied.

[Option 2-1]
Another PUCCH resource for SR may be transmitted. The other PUCCH resource may be, for example, a PUCCH resource (here, a PUCCH resource corresponding to TRP#a) different from the PUCCH resource (here, a PUCCH resource corresponding to TRP#b) used in the first BFR.

[Option 2-2]
A random access preamble (eg, PRACH, message 1 or message A) may be transmitted and the SR for the pending BFR (or the SR for the pending BFR) may be cancelled.

[Option 2-3]
A BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when a BFR is triggered for another TRP (TRP#b where a beam failure has newly occurred) of the SpCell.

The UE may control so that no new UE operations are performed before the timer expires. For example, the UE may perform operations such as waiting for an UL grant transmitted from the network/base station or monitoring the UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-3-1 to UE operation 2-3-3.

<<UE Operation 2-3-1>>
When the MAC CE for BFR for two TRPs of the SpCell is transmitted, the UE may cancel the SR for BFR.

<<UE Operation 2-3-2>>
If a MAC CE for BFR is transmitted for the TRP (e.g., TRP #a) in which beam failure first occurred in the SpCell, but the MAC CE for BFR does not include information on other TRPs in the SpCell, the UE may apply Option 2-1.

<<UE Operation 2-3-3>>
If the MAC CE for BFR is not transmitted, or if the MAC CE including the information of two TRPs of the SpCell is not transmitted (or if the MAC CE does not include information of other TRPs of the SpCell), the UE may apply Option 2-2.

[Option 2-0]
The UE may autonomously control the UL grant (UE implementation). For example, the UE may wait for a certain period of time to receive the UL grant. If the UE cannot receive the UL grant, the UE may apply at least one of the UE actions 2-3-1 to 2-3-3 in the option 2-3.

<Case 2-1-2>
Assume that before the MAC CE for BFR is transmitted, the BFR for the SCell (here, SCell #2) is triggered by the cell-based BFR (or the TRP-based BFR due to beam failure of two TRPs) (see FIG. 8B). In this case, at least one of the following options 2-0, 2-1, and 2-4 may be applied.

[Option 2-1]
Another PUCCH resource for SR may be transmitted. The other PUCCH resource may be, for example, a PUCCH resource (here, a PUCCH resource corresponding to TRP#a) different from the PUCCH resource used in the first BFR.

[Option 2-4]
A BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when BFR for the SCell is triggered.

The UE may control not to perform any new UE operations before the timer expires. For example, the UE may perform operations such as waiting for an UL grant from the network/base station or monitoring an UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-4-1 to 2-4-3.

<<UE Operation 2-4-1>>
When the MAC CE for BFR is transmitted and the MAC CE for BFR includes information on the SpCell/SCell, the UE may cancel the SR for BFR.

<<UE Operation 2-4-2>>
If a MAC CE for BFR for the SpCell is transmitted (a pending SR for BFR is cancelled) but the MAC CE for BFR does not include information of the SCell, an SR may be triggered by the SCell to transmit a default PUCCH resource, transmit two PUCCH resources, or transmit a random PUCCH resource.

<<UE Operation 2-4-3>>
If the MAC CE for BFR has not been transmitted, the UE may transmit a random access preamble (eg, PRACH) and cancel the SR for BFR (eg, a SR for a pending BFR).

[Option 2-0]
The UE may autonomously control the UL grant (UE implementation). For example, the UE may wait for a certain period of time to receive the UL grant. If the UE cannot receive the UL grant, the UE may apply at least one of the UE actions 2-4-1 to 2-4-3 in the option 2-4.

<Case 2-1-3>
Assume that before the MAC CE for BFR is transmitted, BFR for SCell is triggered by BFR per TRP due to beam failure of one TRP (see FIG. 8C). Although FIG. 8C shows a case where beam failure occurs in TRP#b of SCell#1, it can be applied similarly when beam failure occurs in TRP#a of SCell#1. In such a case, at least one of the following options 2-0, 2-5, and 2-6 may be applied.

[Option 2-5]
Another PUCCH resource for SR (e.g., a PUCCH resource corresponding to TRP#a) may be transmitted. In this case, at least one of the following may be taken into consideration: whether the TRP where the beam failure is detected (here, TRP#b)/non-failed TRP (here, TRP#a) is associated with another PUCCH resource, and an indication of the signaling of the relationship between TRPs between cells (or CCs).

If the TRP set in SCell #1 is not associated with another PUCCH resource, a predetermined PUCCH resource/PRACH, etc. may be used. Alternatively, other PUCCH resources may be selected without considering whether the TRP set in SCell #1 is associated with another PUCCH resource or the signaling indication of the relationship between the TRPs between the cells.

[Option 2-6]
A BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when BFR for the SCell is triggered.

The UE may control not to perform any new UE operations before the timer expires. For example, the UE may perform operations such as waiting for an UL grant from the network/base station or monitoring an UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-6-1 to UE operations 2-6-3.

<<UE Operation 2-6-1>>
When the MAC CE for BFR is transmitted and the MAC CE for BFR includes information on the SpCell/SCell, the UE may cancel the SR for BFR.

<<UE Operation 2-6-2>>
If a MAC CE for BFR for the SpCell is sent (a pending SR for BFR is cancelled) but the MAC CE for BFR does not include information of the SCell, then the SCell may trigger an SR and send a default PUCCH resource, two PUCCH resources, or a random PUCCH resource, or the PUCCH resource associated with a TRP for which no beam failure is detected may be sent, taking into account (or not) the indication of the signalling of TRP relationship between cells (or CCs).

<<UE Operation 2-6-3>>
If the MAC CE for BFR has not been transmitted, the UE may transmit a random access preamble (eg, PRACH) and cancel the SR for BFR (eg, a SR for a pending BFR).

[Option 2-0]
The UE may autonomously control the UL grant (UE implementation). For example, the UE may wait for a certain period of time to receive the UL grant. If the UE cannot receive the UL grant, the UE may apply at least one of the UE actions 2-6-1 to 2-6-3 in the option 2-6.

<Case 2-2>
Assume that BFR/SR is triggered by BFR of the SCell (eg, BFR per cell/BFR per TRP) and PUCCH resources are transmitted (see FIG. 9).

Figure 9 shows a case where a cell group includes SpCell, SCell#1 and SCell#2, TRP-based BFR is set for SpCell and SCell#1, and cell-based BFR is set for SCell#2. Here, it shows a case where, when a beam failure is detected on a cell-by-cell basis in SCell#2, the UE transmits an SR for BFR using a specified TRP of the SpCell (or a specified PUCCH resource for SR corresponding to the specified TRP).

The PUCCH resource for a given SR may be a default/random PUCCH resource, a PUCCH resource associated with the TRP where beam failure is detected, or two PUCCH resources.

In this case, after SR is triggered (or PUCCH resources are transmitted), the following cases 2-2-1 to 2-2-3 are assumed before the MAC CE for BFR is transmitted.

<Case 2-2-1>
Assume that before the MAC CE for BFR is transmitted, BFR is triggered for a second SCell (e.g., 2nd SCell) by cell-based BFR or TRP-based BFR based on beam failure of two TRPs (see FIG. 10A). FIG. 10A shows the case where BFR is triggered in both TRPs #a and #b of SCell #1 (2nd SCell).

In such cases, at least one of Options 2-0, Option 2-1 and Option 2-7 below may be applied.

[Option 2-1]
Another PUCCH resource for SR may be transmitted. The other PUCCH resource may be, for example, a PUCCH resource different from the PUCCH resource used in the first BFR.

[Option 2-7]
The BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when the BFR of the second SCell is triggered.

The UE may control not to perform any new UE operations before the timer expires. For example, the UE may perform operations such as waiting for an UL grant from the network/base station or monitoring an UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-7-1 to 2-7-3.

<<UE Operation 2-7-1>>
When a MAC CE for BFR is transmitted and the MAC CE for BFR includes information of two SCells, the UE may cancel the SR for BFR.

<<UE Operation 2-7-2>>
If the MAC CE for BFR for the first SCell #2 (1st SCell) is transmitted (the pending SR for BFR is cancelled) but the MAC CE for BFR does not include information of the second SCell, the SR may be triggered by the second SCell #1 and a default PUCCH resource may be transmitted, or two PUCCH resources may be transmitted, or a random PUCCH resource may be transmitted. Alternatively, the PUCCH resource associated with the TRP for which no beam failure is detected may be transmitted, taking into account (or not taking into account) the indication of the TRP-related signaling between the cells (or CCs).

<<UE Operation 2-7-3>>
If the MAC CE for BFR has not been transmitted, the UE may transmit a random access preamble (eg, PRACH) and cancel the SR for BFR (eg, a SR for a pending BFR).

[Option 2-0]
The UE may autonomously control (UE implementation). For example, the UE may wait for a certain period of time to receive an UL grant. If the UE cannot receive an UL grant, the UE may apply at least one of UE actions 2-8-1 to 2-8-3 in option 2-8.

<Case 2-2-2>
Assume that before the MAC CE for BFR is transmitted, BFR is triggered for a second SCell (e.g., 2nd SCell) by BFR per TRP based on beam failure of one TRP (see FIG. 10B). FIG. 10B shows a case where BFR is triggered in TRP#b of SCell#1 (2nd SCell).

In such cases, at least one of Options 2-0, Option 2-5 and Option 2-8 below may be applied.

[Option 2-5]
Another PUCCH resource for SR may be transmitted. The other PUCCH resource may be, for example, a PUCCH resource different from the PUCCH resource used in the first BFR.

In this case, at least one of the following may be taken into consideration: whether the TRP in which beam failure is detected (here, TRP #b)/non-failed TRP (here, TRP #a) is associated with other PUCCH resources, and an indication of the signaling relationship between TRPs between cells (or CCs).

If the TRP set in SCell #1 is not associated with another PUCCH resource, a predetermined PUCCH resource/PRACH, etc. may be used. Alternatively, other PUCCH resources may be selected without considering whether the TRP set in SCell #1 is associated with another PUCCH resource or the signaling indication of the relationship between the TRPs between the cells.

[Option 2-8]
A BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when the BFR of the second SCell#1 is triggered.

The UE may control not to perform any new UE operations before the timer expires. For example, the UE may perform operations such as waiting for an UL grant from the network/base station or monitoring an UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-8-1 to UE operations 2-8-3.

<<UE Operation 2-8-1>>
When a MAC CE for BFR is transmitted and the MAC CE for BFR includes information of two SCells, the UE may cancel the SR for BFR.

<<UE Operation 2-8-2>>
If a MAC CE for BFR for the first SCell #2 (1st SCell) is transmitted (a pending SR for BFR is cancelled) but the MAC CE for BFR does not include information of the second SCell, an SR may be triggered by the second SCell #1 and a default PUCCH resource may be transmitted, or two PUCCH resources may be transmitted, or a random PUCCH resource may be transmitted.

<<UE Operation 2-8-3>>
If the MAC CE for BFR has not been transmitted, the UE may transmit a random access preamble (eg, PRACH) and cancel the SR for BFR (eg, a SR for a pending BFR).

[Option 2-0]
The UE may autonomously control the UL grant (UE implementation). For example, the UE may wait for a certain period of time to receive the UL grant. If the UE cannot receive the UL grant, the UE may apply at least one of the UE actions 2-7-1 to 2-7-3 in the option 2-7.

<Case 2-2-3>
It is assumed that a beam failure is detected in the SpCell before the MAC CE for BFR is transmitted, and BFR is triggered.

If beam failure is detected in two TRPs of the SpCell, random access preamble (e.g., PRACH) transmission may be initiated and the SR for BFR (e.g., SR for pending BFR) may be canceled.

Alternatively, assume that a beam failure is detected in one TRP and the remaining PUCCH resources (e.g., PUCCH resources different from the PUCCH resource for a given SR) are associated with the TRP where the beam failure is detected. The indication of the TRP-related signaling between CCs may or may not be taken into account. In this case, the transmission of the PRACH may be started and the SR for the BFR (e.g., the SR for the pending BFR) may be canceled.

Assume that a beam failure occurs in one TRP and the transmitted PUCCH resource (e.g., a PUCCH resource for a given SR) is associated with the TRP in which the beam failure is detected. The indication of the signaling of the TRP relationship between CCs may or may not be taken into account. In such a case, at least one of the following options 2-0, 2-1, and 2-9 may be applied.

[Option 2-1]
Another PUCCH resource for SR (eg, a PUCCH resource different from the predetermined PUCCH resource for SR) may be transmitted.

[Option 2-9]
A BFR request (e.g., SR transmission/MAC CE transmission for BFR) may be controlled based on the new timer. The timer may be started when the BFR of the SpCell is triggered.

The UE may control not to perform any new UE operations before the timer expires. For example, the UE may perform operations such as waiting for an UL grant from the network/base station or monitoring an UL grant. After the timer expires, the UE may control the UE operations based on the status of the MAC CE for BFR at the time of timer expiration. For example, the UE may apply at least one of the following UE operations 2-9-1 to 2-9-3.

<<UE Operation 2-9-1>>
When a MAC CE for BFR is transmitted and the MAC CE for BFR includes information on the SCell#2 and the SpCell, the UE may cancel the SR for BFR.

<<UE Operation 2-9-2>>
If the MAC CE for BFR for SCell#2 is transmitted (the pending SR for BFR is cancelled) but the MAC CE for BFR does not include the SpCell's information, the SpCell may trigger an SR and transmit a default PUCCH resource, transmit two PUCCH resources, or transmit a random PUCCH resource. Alternatively, the PUCCH resource associated with the TRP for which no beam failure is detected may be transmitted, taking into account (or not) the indication of the TRP-related signaling between cells (or CCs).

<<UE Operation 2-9-3>>
If a MAC CE for a BFR has not been sent, a random access preamble may be sent and the SR (eg, an SR for a pending BFR) may be cancelled.

[Option 2-0]
The UE may autonomously control the UL grant (UE implementation). For example, the UE may wait for a certain period of time to receive the UL grant. If the UE cannot receive the UL grant, the UE may apply at least one of the UE actions 2-9-1 to 2-9-3 in the option 2-9.

(Third Aspect)
In the third aspect, an example of a BFR procedure will be described in the case where a cell-based BFR is configured in an SpCell and an SR for BFR having two PUCCH resources is configured (or an SR for BFR in which two PUCCH resources are configured is utilized) (see FIG. 6 ).

In such a case, the UE may apply at least one of the following Alt. 3-1 to Alt. 3-3:

[Alt. 3-1]
For the case of SCell BFR with SR triggered, the UE may transmit the default PUCCH resource.

[Alt. 3-2]
For the case of SCell BFR with SR triggered, the UE may transmit two PUCCH resources.

[Alt. 3-3]
If BFR/SR is triggered for an SCell with cell-based BFR, the UE may apply Alt. 3-1/Alt. 3-2. If BFR/SR is triggered for an SCell with TRP-based BFR, the UE may transmit the default PUCCH resource, two PUCCH resources, a random PUCCH resource, or a PUCCH resource associated with a TRP with no beam failure detected (non-failed TRP). The UE may select the PUCCH resource with or without considering the indication of the signaling of the TRP relationship between cells (or CCs).

In addition, when SR is triggered for BFR, if BFR is triggered in another cell before the MAC CE for BFR is transmitted, any of the methods shown in the second aspect may be applied.

If two PUCCH resources for BFR SR are transmitted, no MAC CE for BFR is transmitted, and BFR is triggered in another cell, the UE may autonomously control the UE operation (UE implementation). For example, a smart UE (e.g., smart UE) may control (e.g., control in the same way as Rel. 16) to wait for an UL grant from the network/base station since there is no SR to be triggered (there is only one SR for BFR).

In Rel. 16, if an SR for BFR is transmitted, a MAC CE for BFR is not transmitted, and a BFR for another SCell is triggered, the UE's operation is controlled based on the UE's implementation. The UE waits to receive an UL grant from the network, and if the UE obtains the UL grant and transmits a MAC CE containing information of all SCells in which beam failure has been detected, the SR is canceled and the BFR is completed. If the UE obtains an UL grant and transmits a MAC CE for BFR, but the MAC CE for BFR does not contain information of the SCell in which a beam failure has been detected, but only contains information of the cell in which a beam failure has been detected before, the SR (pending SR) triggered in the previous SCell is canceled and the BFR of the previous SCell may be completed. Meanwhile, the SR for BFR of the new SCell may be triggered again.

If the transmission of two PUCCH resources corresponding to SR is supported by higher layer parameters, etc., the UE may not assume that two PUCCH resources are set in overlapping time resources. The base station may control so that two PUCCH resources are not set in overlapping time resources.

(Fourth aspect)
In a fourth aspect, an example of a BFR procedure is described where BFR is triggered for multiple cells during a period of time (eg, simultaneously).

The case where BFR is triggered simultaneously for multiple cells can be considered similar to the case where BFR is triggered for one cell and an SR for BFR is triggered, and then BFR is triggered in other cells before the MAC CE for BFR is transmitted.

Therefore, in cases where BFR is triggered simultaneously for multiple cells, the configuration shown in the second aspect/the configuration shown in the third aspect may be applied.

<Variations>
If BFR is triggered for multiple cells simultaneously, the UE may apply Alt. 4-1/Alt. 4-2 below.

[Alt. 4-1]
The UE may transmit the PUCCH resource for SR corresponding to the other TRP when the beam failure is detected in only one TRP in multiple CCs, taking into consideration the signaling indicating the TRP relationship between cells (or CCs). Also, the UE may control to transmit two PUCCH resources when the beam failure is detected in two TRPs in consideration of multiple CCs.

[Alt. 4-2]
The UE may first consider the cell with the lowest index and send the PUCCH transmission for SR according to the BFD result of the cell with the lowest index, after which the UE may control the BFR operation for other cells based on the second/third aspects.

<BFD with 2TRP per cell>
The case where beam failure is detected in two TRPs in one cell can be considered similar to the case where a TRP-based BFR is triggered for one cell, an SR for the BFR is transmitted, and then a TRP-based BFR is triggered for other TRPs of the cell before a MAC CE for the BFR is transmitted.

Therefore, in cases where beam disturbance is detected in two TRPs in one cell, the configuration shown in the second aspect/the configuration shown in the third aspect may be applied.

(Fifth aspect)
In the fifth aspect, an example of a BFR procedure different from the first to fourth aspects will be described.

The UE may apply the following operations for cases 1 to 3 in FIG. 4.

<Case 1>
In case 1, the beam failure of the TRP unit of the SCell in which the beam failure is detected in one TRP (for example, TRP #a of SCell #1) triggers the SR for BFR and transmits the PUCCH resource for SR. Then, before the MAC CE for BFR is transmitted (or before the SR is canceled), the beam failure is detected in the other TRP (for example, TRP #b of SCell #2, or both TRP #a and #b of SCell #2), and the other SCell is also detected as a beam failure in the TRP unit.

In such a case, the UE may control the transmission of information about the BFR that has occurred in both TRP#a of SCell#1 and TRP#b of SCell#2 (information about both TRPs) in the MAC CE for BFR without transmitting a PUCCH for SR for the BFR of TRP#b (see FIG. 11A).

As a result, even if the UE detects beam failure in a TRP of a certain cell after BFR/SR for BFR is triggered in another TRP (and before transmitting MAC CE for BFR), the UE can transmit information about the two TRPs in which beam failure was detected without delay using MAC CE for BFR.

<Case 2>
It is assumed that beam failures on a TRP basis are detected simultaneously in multiple SCells, and the TRP in which beam failure occurs is different in each SCell (for example, BF of TRP#a in SCell#1 and BF of TRP#b in SCell#2).

In such a case, the UE may control to transmit one SR PUCCH to either TRP#a of SCell#1 or TRP#b of SCell#2 (see FIG. 11B). The UE may autonomously decide which SR PUCCH to transmit, or may be defined/set in advance. When transmitting the BFR MAC CE of step 2, the UE may control to transmit both BFR information related to TRP#a of SCell#1 and BFR information related to TRP#b of SCell#2 in the BFR MAC CE.

<Case 3>
It is assumed that the TRP set in the SpCell may be different from the TRP set in the SCell.

In such a case, if there is a PUCCH for SR corresponding to the TRP in which beam failure is detected in any cell, the UE may control to transmit one PUCCH for SR for the TRP in which beam failure is detected. In transmitting the MAC CE for BFR in step 2, the UE may control to transmit the MAC CE for BFR including information regarding which TRP of which SCell BFR has occurred.

If there is no PUCCH for SR corresponding to the TRP in which beam failure is detected in any cell, the UE may transmit a normal SR, a PUCCH SR for each cell (or a PUCCH for SR), or a default PUCCH SR to obtain an UL grant (see FIG. 11C). In transmitting the MAC CE for BFR in step 2, the UE may control the transmission of the MAC CE for BFR to include information regarding which TRP of which SCell BFR occurred.

In the absence of normal SR or cell-specific PUCCH SR, the UE may be controlled to transmit PRACH.

(UE Capability Information)
In the above first to fifth aspects, the following UE capabilities may be configured. Note that the following UE capabilities may be read as parameters (e.g., higher layer parameters) configured in the UE from a network (e.g., a base station).

When TRP-based BFR is not configured in the SpCell, UE capability information regarding whether or not SR for BFR with two PUCCH resources configured may be defined.

UE capability information may be defined regarding whether or not to support notification/indication of TRP relationships (e.g., beam relationship, QCL-typed RS relationship) between cells (or CCs).

UE capability information may be defined regarding whether or not to support configuration of CC lists for CCs that share the same TRP relationship (e.g., beam relationship, QCL-typed RS relationship).

After SR is triggered for one cell, UE capability information may be defined regarding whether or not other cells support a new timer for BFR.

UE capability information regarding whether or not to support transmitting two PUCCH resources for SR for BFR may be defined.

The first to fifth aspects may be applied to a UE that supports/reports at least one of the above-mentioned UE capabilities. Alternatively, the first to fifth aspects may be applied to a UE configured by the network.

(Wireless communication system)
A configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination of these methods.

12 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 may be a system that realizes communication using Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) specified by the Third Generation Partnership Project (3GPP).

In addition, the wireless communication system 1 may support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (Master Node (MN)) and the NR base station (gNB) is the secondary node (Secondary Node (SN)). In NE-DC, the NR base station (gNB) is the MN and the LTE (E-UTRA) base station (eNB) is the SN.

The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (e.g., dual connectivity in which both the MN and the SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are arranged within the macrocell C1 and form a small cell C2 that is narrower than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The arrangement and number of each cell and user terminal 20 are not limited to the aspect shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as base station 10.

The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CC) and dual connectivity (DC).

Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). Macro cell C1 may be included in FR1, and small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band above 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may correspond to a higher frequency band than FR2.

In addition, the user terminal 20 may communicate using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD) in each CC.

Multiple base stations 10 may be connected by wire (e.g., optical fiber conforming to the Common Public Radio Interface (CPRI), X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, base station 11, which corresponds to the higher-level station, may be called an Integrated Access Backhaul (IAB) donor, and base station 12, which corresponds to a relay station, may be called an IAB node.

The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include at least one of, for example, an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

The user terminal 20 may be a terminal compatible with at least one of the communication methods such as LTE, LTE-A, 5G, etc.

In the wireless communication system 1, a wireless access method based on Orthogonal Frequency Division Multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and uplink (UL), Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), etc. may be used.

The radio access method may be called a waveform. In the wireless communication system 1, other radio access methods (e.g., other single-carrier transmission methods, other multi-carrier transmission methods) may be used for the UL and DL radio access methods.

In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as the downlink channel.

In addition, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc. may be used as an uplink channel.

User data, upper layer control information, System Information Block (SIB), etc. are transmitted by the PDSCH. User data, upper layer control information, etc. may be transmitted by the PUSCH. In addition, Master Information Block (MIB) may be transmitted by the PBCH.

Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, downlink control information (Downlink Control Information (DCI)) including scheduling information for at least one of the PDSCH and the PUSCH.

In addition, the DCI for scheduling the PDSCH may be called a DL assignment, DL DCI, etc., and the DCI for scheduling the PUSCH may be called a UL grant, UL DCI, etc. In addition, the PDSCH may be replaced with DL data, and the PUSCH may be replaced with UL data.

A control resource set (COntrol REsource SET (CORESET)) and a search space may be used to detect the PDCCH. The CORESET corresponds to the resources to search for DCI. The search space corresponds to the search region and search method of PDCCH candidates. One CORESET may be associated with one or multiple search spaces. The UE may monitor the CORESET associated with a certain search space based on the search space configuration.

One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be referred to as a search space set. Note that the terms "search space," "search space set," "search space setting," "search space set setting," "CORESET," "CORESET setting," etc. in the present disclosure may be read as interchangeable.

The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery confirmation information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK/NACK, etc.), and a scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

In this disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, as the DL-RS, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted.

The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including an SS (PSS, SSS) and a PBCH (and a DMRS for the PBCH) may be referred to as an SS/PBCH block, an SS Block (SSB), etc. In addition, the SS, SSB, etc. may also be referred to as a reference signal.

In addition, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may be called a user equipment specific reference signal (UE-specific Reference Signal).

(Base station)
13 is a diagram showing an example of a configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140 may each be provided in one or more units.

In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and the base station 10 may be assumed to have other functional blocks necessary for wireless communication. Some of the processing of each part described below may be omitted.

The control unit 110 controls the entire base station 10. The control unit 110 can be composed of a controller, a control circuit, etc., which are described based on a common understanding in the technical field to which the present disclosure relates.

The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transmission and reception unit 120, the transmission and reception antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transmission and reception unit 120. The control unit 110 may perform call processing of communication channels (setting, release, etc.), status management of the base station 10, management of radio resources, etc.

The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be composed of a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on a common understanding in the technical field related to the present disclosure.

The transmitting/receiving unit 120 may be configured as an integrated transmitting/receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 1211 and an RF unit 122. The receiving unit may be composed of a reception processing unit 1212, an RF unit 122, and a measurement unit 123.

The transmitting/receiving antenna 130 may be constructed from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

The transceiver unit 120 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc.

The transceiver unit 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

The transceiver unit 120 (transmission processing unit 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

The transceiver unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 130.

On the other hand, the transceiver unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 130.

The transceiver unit 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, and acquire user data, etc.

The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30, other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

In addition, the transmitting unit and receiving unit of the base station 10 in the present disclosure may be constituted by at least one of the transmitting/receiving unit 120, the transmitting/receiving antenna 130, and the transmission path interface 140.

The transceiver unit 120 may transmit at least one of configuration information for beam fault recovery for cells included in the cell group and configuration information for a reference signal for beam fault detection.

The control unit 110 may control the number of control channel resources corresponding to a scheduling request (SR) for beam fault recovery set in a cell group or a specific cell in a cell group, depending on at least one of the setting information for beam fault recovery and the setting information for a reference signal for beam fault detection.

(User terminal)
14 is a diagram showing an example of the configuration of a user terminal according to an embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the control unit 210, the transceiver unit 220, and the transceiver antenna 230 may each include one or more.

In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and the user terminal 20 may be assumed to have other functional blocks necessary for wireless communication. Some of the processing of each part described below may be omitted.

The control unit 210 controls the entire user terminal 20. The control unit 210 can be composed of a controller, a control circuit, etc., which are described based on a common understanding in the technical field to which the present disclosure relates.

The control unit 210 may control signal generation, mapping, etc. The control unit 210 may control transmission and reception, measurement, etc. using the transmission and reception unit 220 and the transmission and reception antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transmission and reception unit 220.

The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured from a transmitter/receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on a common understanding in the technical field related to the present disclosure.

The transmission/reception unit 220 may be configured as an integrated transmission/reception unit, or may be composed of a transmission unit and a reception unit. The transmission unit may be composed of a transmission processing unit 2211 and an RF unit 222. The reception unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

The transmit/receive antenna 230 may be configured as an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

The transceiver unit 220 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), etc.

The transceiver unit 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

The transceiver unit 220 (transmission processing unit 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit sequence to be transmitted, and output a baseband signal.

In addition, whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the above-mentioned transmission processing to transmit the channel using a DFT-s-OFDM waveform, and if not, it is not necessary to perform DFT processing as the above-mentioned transmission processing.

The transceiver unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 230.

On the other hand, the transceiver unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 230.

The transceiver unit 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, and acquire user data, etc.

The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

In addition, the transmitting unit and receiving unit of the user terminal 20 in the present disclosure may be constituted by at least one of the transmitting/receiving unit 220 and the transmitting/receiving antenna 230.

The transceiver unit 220 may receive at least one of configuration information for beam fault recovery for cells included in the cell group and configuration information for a reference signal for beam fault detection.

The control unit 210 may determine the number of control channel resources corresponding to a scheduling request (SR) for beam fault recovery set in a cell group or a specific cell in a cell group based on at least one of the setting information for beam fault recovery and the setting information for a reference signal for beam fault detection.

When different transmission and reception points are set between a specific cell and other cells included in a cell group, and a beam failure is detected on a transmission and reception point basis in the other cells, the control unit 210 may control the specific cell to transmit a scheduling request for beam failure recovery using predetermined uplink control channel resources.

When an SR for beam fault recovery is triggered for a certain transmission/reception point of a specific cell, and a beam fault is detected at another transmission/reception point or a beam fault recovery at another transmission/reception point is triggered before the transmission of a MAC CE corresponding to the SR, the control unit 210 may control the beam fault recovery request to be made using a specified resource other than the uplink control channel resource corresponding to a certain transmission point.

When cell-based beam fault recovery is configured for a particular cell and multiple uplink control channel resources are configured for the SR for beam fault recovery, the control unit 210 may control the SR triggered for beam fault recovery of other cells to be transmitted using predetermined uplink control channel resources.

(Hardware configuration)
The block diagrams used in the description of the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or may be realized using two or more devices that are physically or logically separated and directly or indirectly connected (for example, using wires, wirelessly, etc.). The functional blocks may be realized by combining the one device or the multiple devices with software.

Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the transmission function may be called a transmitting unit, transmitter, etc. In either case, as described above, there are no particular limitations on the method of realization.

For example, a base station, a user terminal, etc. in one embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 15 is a diagram showing an example of the hardware configuration of a base station and a user terminal according to one embodiment. The above-mentioned base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

In this disclosure, the terms apparatus, circuit, device, section, unit, etc. may be read interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the figures, or may be configured to exclude some of the devices.

For example, although only one processor 1001 is shown, there may be multiple processors. Also, the processing may be performed by one processor, or the processing may be performed by two or more processors simultaneously, sequentially, or using other techniques. The processor 1001 may be implemented by one or more chips.

Each function in the base station 10 and the user terminal 20 is realized, for example, by loading a specific software (program) onto hardware such as the processor 1001 and memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and the storage 1003.

The processor 1001, for example, operates an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, registers, etc. For example, at least a portion of the above-mentioned control unit 110 (210), transmission/reception unit 120 (220), etc. may be realized by the processor 1001.

The processor 1001 also reads out programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to these. The programs used are those that cause a computer to execute at least some of the operations described in the above-mentioned embodiments. For example, the control unit 110 (210) may be realized by a control program stored in the memory 1002 and running on the processor 1001, and other functional blocks may be realized in a similar manner.

The memory 1002 is a computer-readable recording medium and may be composed of at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically EPROM (EEPROM), a Random Access Memory (RAM), or other suitable storage media. The memory 1002 may be called a register, a cache, a main memory, or the like. The memory 1002 may store executable programs (program codes), software modules, and the like for implementing a wireless communication method according to one embodiment of the present disclosure.

Storage 1003 is a computer-readable recording medium and may be constituted by at least one of, for example, a flexible disk, a floppy (registered trademark) disk, a magneto-optical disk (e.g., a compact disk (Compact Disc ROM (CD-ROM)), a digital versatile disk, a Blu-ray (registered trademark) disk), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, stick, key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

The communication device 1004 is hardware (transmission and reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., to realize at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, the above-mentioned transmission and reception unit 120 (220), transmission and reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission and reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, a Light Emitting Diode (LED) lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one configuration (e.g., a touch panel).

In addition, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

Furthermore, the base station 10 and the user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized using the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

(Modification)
In addition, the terms described in this disclosure and the terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be read as mutually interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may be called a pilot, a pilot signal, or the like depending on the applied standard. A component carrier (CC) may also be called a cell, a frequency carrier, a carrier frequency, or the like.

A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

Here, the numerology may be a communication parameter applied to at least one of the transmission and reception of a signal or channel. The numerology may indicate at least one of, for example, SubCarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame configuration, a specific filtering process performed by the transceiver in the frequency domain, and a specific windowing process performed by the transceiver in the time domain.

A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.). A slot may also be a time unit based on numerology.

A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting a signal. A different name may be used for the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in this disclosure may be read as interchangeable with each other.

For example, one subframe may be called a TTI, multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal by allocating radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

A TTI may be a transmission time unit for a channel-coded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) in which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit of scheduling. In addition, the number of slots (minislots) constituting the minimum time unit of scheduling may be controlled.

A TTI having a time length of 1 ms may be called a normal TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, normal subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

Note that a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length less than the TTI length of a long TTI and equal to or greater than 1 ms.

A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, and may be, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

In addition, an RB may include one or more symbols in the time domain and may be one slot, one minislot, one subframe, or one TTI in length. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

A resource block may also be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

A Bandwidth Part (BWP), which may also be referred to as partial bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by an index of the RB relative to a common reference point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

The BWP may include an UL BWP (BWP for UL) and a DL BWP (BWP for DL). One or more BWPs may be configured for a UE within one carrier.

At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal/channel outside the active BWP. Note that the terms "cell", "carrier", etc. in this disclosure may be read as "BWP".

The above-mentioned structures of radio frames, subframes, slots, minislots, and symbols are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, as well as the number of symbols in a TTI, the symbol length, and the cyclic prefix (CP) length can be changed in various ways.

In addition, the information, parameters, etc. described in the present disclosure may be represented using absolute values, may be represented using relative values from a predetermined value, or may be represented using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

The names used for parameters, etc. in this disclosure are not limiting in any respect. Furthermore, the formulas, etc. using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and the various names assigned to these various channels and information elements are not limiting in any respect.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

In addition, information, signals, etc. may be output from a higher layer to a lower layer and/or from a lower layer to a higher layer. Information, signals, etc. may be input/output via multiple network nodes.

Input/output information, signals, etc. may be stored in a specific location (e.g., memory) or may be managed using a management table. Input/output information, signals, etc. may be overwritten, updated, or appended. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

Notification of information is not limited to the aspects/embodiments described in the present disclosure, and may be performed using other methods. For example, notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB), etc.), Medium Access Control (MAC) signaling), other signals, or combinations thereof.

The physical layer signaling may be called Layer 1/Layer 2 (L1/L2) control information (L1/L2 control signal), L1 control information (L1 control signal), etc. The RRC signaling may be called an RRC message, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc. The MAC signaling may be notified, for example, using a media access control control element (MAC Control Element (CE)).

In addition, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

The determination may be based on a value represented by a single bit (0 or 1), a Boolean value represented as true or false, or a numerical comparison (e.g., with a predetermined value).

Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Additionally, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and/or wireless technologies (such as infrared, microwave, etc.), then these wired and/or wireless technologies are included within the definition of a transmission medium.

As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., a base station).

In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "Reference Signal (RS) port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," "transmitting and receiving point," etc. may be used interchangeably.

In this disclosure, terms such as "Base Station (BS)", "Radio base station", "Fixed station", "NodeB", "eNB (eNodeB)", "gNB (gNodeB)", "Access point", "Transmission Point (TP)", "Reception Point (RP)", "Transmission/Reception Point (TRP)", "Panel", "Cell", "Sector", "Cell group", "Carrier", "Component carrier", etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small base station for indoor use (Remote Radio Head (RRH))). The term "cell" or "sector" refers to a part or the entire coverage area of at least one of the base station and base station subsystems that provide communication services in this coverage.

In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a wireless communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may include a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

In addition, the base station in the present disclosure may be read as a user terminal. For example, each aspect/embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the user terminal 20 may be configured to have the functions possessed by the above-mentioned base station 10. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "side"). For example, the uplink channel, the downlink channel, etc. may be read as a side channel.

Similarly, the user terminal in the present disclosure may be interpreted as a base station. In this case, the base station 10 may be configured to have the functions of the user terminal 20 described above.

In the present disclosure, operations that are described as being performed by a base station may in some cases also be performed by its upper node. In a network including one or more network nodes having base stations, it is clear that various operations performed for communication with terminals may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc.), or a combination thereof.

Each aspect/embodiment described in this disclosure may be used alone, in combination, or switched as the implementation progresses. In addition, the processing procedures, sequences, flow charts, etc. of each aspect/embodiment described in this disclosure may be reordered as long as there is no inconsistency. For example, the methods described in this disclosure present elements of various steps using an example order and are not limited to the particular order presented.

Each aspect/embodiment described in this disclosure may be a part of any of the following: Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE The present invention may be applied to systems using 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable wireless communication methods, or to next-generation systems that are expanded/modified/updated based on these. In addition, the present invention may be applied to a combination of multiple systems (for example, a combination of LTE or LTE-A and 5G).

As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

Any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

The term "determining" as used in this disclosure may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, and the like.

"Determining" may also be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), etc.

In addition, "judgment" may be considered to be "judging" resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" may be considered to be "judging" some action.

In addition, "judgment (decision)" may be interpreted as "assuming," "expecting," "considering," etc.

As used in this disclosure, the terms "connected" and "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between the elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, and the like, as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, and the like, as some non-limiting and non-exhaustive examples.

In this disclosure, the term "A and B are different" may mean "A and B are different from each other." In addition, the term may mean "A and B are each different from C." Terms such as "separate" and "combined" may also be interpreted in the same way as "different."

When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Additionally, the term "or," as used in this disclosure, is not intended to be an exclusive or.

In this disclosure, where articles have been added by translation, such as a, an, and the in English, this disclosure may include that the nouns following these articles are in the plural form.

Although the invention disclosed herein has been described in detail above, it is clear to those skilled in the art that the invention disclosed herein is not limited to the embodiments described herein. The invention disclosed herein can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description of the disclosure is intended as an illustrative example and does not impose any limiting meaning on the invention disclosed herein.

Claims (5)

A receiving unit that receives beam failure recovery (BFR) setting information for a special cell (SpCell) and a secondary cell (SCell) included in a cell group;
A terminal having a control unit that controls BFR to be performed using resources other than a physical uplink control channel (PUCCH) resource corresponding to the first TRP when a scheduling request (SR) for BFR for a first transmission/reception point (TRP) of the SpCell is triggered and a BFR for a second TRP of the SpCell is triggered before a medium access control control element (MAC CE) corresponding to the SR is transmitted . The terminal of claim 1 , wherein the resource other than the PUCCH resource is a Physical Random Access Channel (PRACH) resource. Receiving beam failure recovery (BFR) configuration information for a special cell (SpCell) and a secondary cell (SCell) included in a cell group;
When a scheduling request (SR) for BFR for a first transmission/reception point (TRP) of the SpCell is triggered and a BFR for a second TRP of the SpCell is triggered before a medium access control control element (MAC CE) corresponding to the SR is transmitted, a control step is performed to perform BFR using resources other than a physical uplink control channel (PUCCH) resource corresponding to the first TRP . A transmitter that transmits beam failure recovery (BFR) configuration information for a special cell (SpCell) and a secondary cell (SCell) included in a cell group;
A base station having a control unit that controls BFR to be performed using resources other than a physical uplink control channel (PUCCH) resource corresponding to the first TRP when a scheduling request (SR) for BFR for a first transmission/reception point (TRP) of the SpCell is triggered and a BFR for a second TRP of the SpCell is triggered before a medium access control control element (MAC CE) corresponding to the SR is received . A system having a terminal and a base station,
The terminal includes:
A receiving unit that receives beam failure recovery (BFR) setting information for a special cell (SpCell) and a secondary cell (SCell) included in a cell group;
A control unit that controls the BFR to be performed using resources other than a physical uplink control channel (PUCCH) resource corresponding to the first TRP when a scheduling request (SR) for BFR for a first transmission/reception point (TRP) of the SpCell is triggered and a BFR for a second TRP of the SpCell is triggered before a medium access control control element (MAC CE) corresponding to the SR is transmitted,
The base station,
The system includes a transmission unit that transmits the setting information.

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